Circuit-interrupter.



R. E. HELLMUND.

1CIRCUIT INTERRUPTER.

APPLICATION FILED JULY 6.1911.

Patented J uly 2, 1918.

[0 molar;

Z0 motors.

WITNESSES:

n A AU V INVENTOR V Edda/f [f/d/muhd ATTORNEY RUDOLF E. HELLMUND, 0F SWISSVALE, PENNSYLVANIA,

ASSIGNOR T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CIRC UIT-INTERRUPTER.

Application filed July 6, 1917.

T 0 all whom it may concern Be it known that I, RUnoLr E. HELLMUND, a citizen of the United States, and a resident of Swissvale. in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in CircuitInterrupters. of which the following is a specification.

My invention relates to circuit interrupt ers and particularly to means for controlling the tripping of such devices under .predetermined conditions.

One object of my invention is to provide an interrupter for an alternating-current circuit that shall be adapted to be tripped only when an overload current having a symmetrical wave shape traverses the circuit.

Another object of my invention is to provide means that shall be adapted to pre clude the operation of a circuit interrupter when the current traversing the circuit has a unidirectional component.

A further object of my invention is to provide a device of the above indicated character that shall be simple and inexpensive to construct and effective in its operation.

Ileretofore. considerable trouble has been encountered in alternating-current railway vehicles because of the tripping of the circuit interrupter when the pantograph is raised or when it bounces. That is, the action of the pantograph causes a relatively high unidirectional instantaneous current to traverse the circuit which may be suflicient to trip the interrupter. This can be overcome by imposing a time element in the operation of the interrupter but it will render the interrupter ineffective for overloads of relatively short duration.

In view of the above, I provide a that is responsive to a current havin a unidirectional oomponent, and adapt this relay to preclude the tripping of the interrupter when oscillations obtain on the circuit.

In the accompanying drawings, Figure 1 1s a diagrammatic view of an electrical circuit embodying my invention; Fig. 2 is a diagrammatic view of an electrical circuit embodying a modified form of my invention, and Figs. 3 and 4 are diagrams illustrating the wave shape of the current traversing a circuit incident to the raising or bouncing of the pantograph or current collector.

In Fig. 1 of the drawings, the motors (not shown) of an electric locomotive are connected through a circuit interrupter 1 and a relay Specification of Letters Patent.

Patented July 2, 1918. Serial No. 178,952.

pantograph 2 to a trolley conductor 3. Relays 1 and 5 are adapted to control the tripping of the circuit interrupter 1 under predetermined conditions.

A latch or circuit controlling member 6 is provided for holding the interrupter 1 in its closed position and is adapted to be actuated by the overload relay 1 that comprises a magnetizable core member 7 and a winding 8. The relay 5 comprises an armature 9, a field magnet winding 10, a source 11 of direct-current electromotive force for energizing the winding 10, a cam member 12 and springs 13 for normally holding the cam member in the position shown in Fig. 1 of the drawings. A resistor 14 is connected in the circuit between the pantograph 2 and the motors (not shown), and the circuit comprising the armature winding 9 of the relay 5 and the winding 8 of the relay 4 are connected in shunt relation to the resistor 14:.

The cam member 12 is normally held by the springs 13 in suchposition that when an overload obtains on the motors, the movable core member 7 of the relay 4 may be moved upwardly to permit the circuit interrupter 1 to be tripped. However, if the pantograph 2 bounces into and out of engagement with the trolley conductor 3, a unidirectional surge of relatively high instantaneous value substantially asshown in Figs. 3 and 4 of the drawings is set up. Since this surge is of a relatively high value, it would effect the tripping of the circuit interrupter 1 if the relay 5 were not pro vided. However, since this surge is unidirectional in form, it cooperates with the field winding 10 of the relay 5 and causes the armature 9 and, consequently, the cam member 12 to be turned in the one or the other direction in accordance with the direction of the surge and thereby causes the curved portion of the cam to assume such position that the relay 4 is prevented from raising the latch member 6 to such position as to permit the interrupter 1 to trip. It will, of course, be understood that the re lay 5 must operate in relatively less time than the relay 4, and to insure this the relay 4 must be relatively slow in operation.

In Fig. 2 of the drawings, I provide a quick-acting relay device 15 that is adapted to control a circuit interrupter 16 through a circuit controlling lever 17, a trip coil 18 and a source 19 of electromotive force.

The relay device 15 comprises two motors 20 and 21 having armatures 22 and 23, series-connected field windings 24 and 25 and separately excited field windings 26 and 27. The field windings 26 and 27 are connected in series relation with a source 28 of direct current and the circuit comprising the field windings 24 and 25 and the armatures 22 and 23 is connected in shunt relation to the resistor 14. The motors 20 and 21 are provided with cam members 29 and 30, respectively, that are adapted to normally engage the lever arm 17 to preclude a spring 31 from so moving the same as to complete the circuit of the trip coil 18.

Under ordinary alternating-current overloads, the windings 26 and 27 are ineffective and the windings 24 and 25 are adapted to cooperate with the windings of the arma tures 22 and 23 to turn the cam members 29 and 30 a predetermined distance in a counter-clockwise direction -to assume such position as to permit the spring 31 to move the arm 17 upwardly. However, if the bouncing of the pantograph 2 induces a unidirectional surge, such as shown in Fig. 3 of the drawings, the direct-current field winding of one of the motors will assist its series field winding and oppose it in the other motor. Also, if the unidirectional current be such as shown in Fig. 4 of the drawings, the direct-current field winding of -the other mo tor will assist its series field winding and oppose it in the other motor. That is, the only condition under which both of the motors 20 and 21 will assume such position as to permit the lever 17 to move upwardly will be when a pure symmetrical alternating-current overload traverses the resistor 14. When the unidirectional surge is in one direction, motor 20 will remain stationary and the motor 21 will move, and when the unidirectional surge is in the other direction, the motor 21 will remain stationary and the motor 20 will be moved. Thus, if the operation of the motors 20 and 21 is set for relatively low alternating-current overloads, the circuit interrupter 16 will be tripped only when an alternating-current overload traverses the circuit and not when an oscillation is set up therein.

It will be understood that my invention is not limited to the specific structures illustrated as it may be variously modified without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention 1. In an electric circuit, the combination with a circuit controlling member, of means for actuating the same when an overload obtains on the circuit and for preventing its operation when a surge obtains thereon.

2. In an alternating-current circuit, the combination with a circuit controlling member, of means for actuating the same when an overload current having a predetermined wave shape traverses the circuit and for preventing its operation when the wave shape of the current traversing the circuit has other predetermined forms.

In an alternating-current circuit, the combination with a circuit controlling member, of means for actuating the same only when an overload current-liaving a symmetrical wave shape traverses the circuit.

4. In an alternating-currcnt circuit, the combination with a circuit. controlling member, of means for actuating the same when an overload traverses the circuit and for preventing its operation when the overload current wave has a-unidirectional component.

In an alternating-current circuit, the combination with a circuit controlling member, of means for actuating the same only when a current having a symmetrical wave shape traverses the circuit. I

6. In an alternating-current circuit, the combination with a movable member, and means for actuating the same, of means for so controlling the movable member that it is prevented from moving when the current traversing the circuit has an unsymmetrical wave shape.

7. In an alternating-current circuit, the combination with a movable member and a spring for actuating the same, of a relay for preventing its movement when the current traversing the circuit has a unidirectional component therein.

8. In an alternating-current circuit, the combination with a movable member and a spring for actuating the same, of a relay for preventing its movement when a unidirectional oscillation obtains on the circuit.

9. In an alternating-current circuit, the combination with a movable member and resilient means for actuating the same, of two cam members for precluding the movement of the movable member when the current traversing the circuit has a unidirectional component therein.

10. In an alternating-current circuit, the combination with a movable member and resilient means for actuating the same, of

two cam members for permitting the move-- ment of the movable member when an overload having a symmetrical current wave traverses the circuit and for preventing its movement when the current wave is unsymmetrical.

In testimony whereof, I have hereunto subscribed my name this 28th day of June,

RUDOLF E. HELLMUND. 

